1. Field of the Invention
The present invention relates in general to automatic transmissions and more particularly to a governor arrangement in an automatic transmission.
2. Description of the Prior Art
An example of a prior art governor arrangement in an automatic transmission is disclosed in "Service Manual for Toyota A140 Automatic Transmission", published in May, 1985 by Toyota Motor Co., Ltd. and also shown in FIGS. 3 to 5.
Referring to FIGS. 3 to 5, the automatic transmission is of the kind for use in a transversely mounted front-engine front-drive vehicle and there is disposed within a transmission case 01 a power train for transmission of power from an engine 02. The power train includes a main power train 03, output gear 04, idler gear 05, final drive gear 06 and differential gear 07 and is constructed so that the output gear center axis Oo, idler gear center axis Oa and final drive gear center axis Of are parallel to each other. A governor 08 is adapted to receive rotary motion from an idler shaft 09 provided with the idler gear 05 and arranged so that the governor shaft O8a intersects the idler shaft 09 at right angles when viewed in a plane of projection parallel to the idler gear center axis Oa and the governer shaft center axis Og.
The reason why the governor 08 is adapted to receive rotary motion from the idler shaft 9 is that if adapted to receive rotary motion from the output gear 04 the axial length of the transmission is increased and if adapted to receive rotary motion from a differential gear section its rotary motion is affected by a final gear ratio, both therefore being undesirable. Further, it is because there is a sufficient space for installation of the governor 08 around the idler shaft 09.
In FIGS. 3 to 5, indicated by 010 is a converter housing, by 011 a differential receiving transmission case portion, by 012 a drive shaft joint, by 013 a drive shaft, by 014 a manual shaft, by 015 a control valve, by 016 an oil strainer and by 017 an oil pan.
The prior art arrangement has the following problems.
(1) The governor shaft O8a is interposed between the output gear center axis Oo and the idler gear center axis Oa. Due to this, the length indicated by "A" in FIG. 3 (the vertical distance between the output gear center axis Oo and the idler gear center axis Oa) and the length indicated by "B" in FIG. 3 (the vertical distance between the output gear center axis Oo and the lowest part of the automatic transmission) are large.
Accordingly, if the layout of the automatic transmission is made by giving preference to the ground clearance "H", the engine hood must be arranged in a high position, thus causing a design restriction. On the other hand, if the layout of the automatic transmission is made by giving preference to the position of the engine hood, the ground clearance "H" becomes small, thus causing a problem that the transmission is likely to contact the ground.
(2) The drive shaft joint 012 and the drive shaft 013 stand as obstacles in the path or way through which the governor 08 is to be drawn upon removal.
Due to this, inspection and exchange of the governor 08 cannot be carried out with the drive shaft joint 012 and the drive shaft 013 being installed in place but it is necessary to remove the drive shaft joint 012 and the drive shaft 013 prior to removal of the governer 08 for inspection or exchange.
Accordingly, it is impossible to inspect or exchange the governer 08 when the drive shaft, etc. are installed in place.